Flexural Pivot

ABSTRACT

A flexural pivot can include a plurality of flexure support members, each flexure support member having a plurality of flexure openings and a plurality of wells each in fluid communication with a respective flexure opening. The flexural pivot can also include at least one flexure to rotatably couple the plurality of flexure support members to one another. The at least one flexure can have first and second flexible blades arranged in a cross configuration. The first and second flexible blades can be disposed in the flexure openings of the flexure support members, and coupling material deposited in the flexure openings can couple the first and second flexible blades to the flexure support members.

RELATED APPLICATIONS

This is a divisional application of U.S. application Ser. No.15/448,538, filed Mar. 2, 2017, entitled “Flexural Pivot”, which isincorporated by reference in its entirety herein.

BACKGROUND

Flexural pivots are devices that permit mechanical members to pivotabout a common axis relative to each other through a limited anglerange.

Because angular motion is accomplished through flexing of elasticflexural elements, rather than contact surface displacement, flexuralpivots operate without friction and thus without a need for lubrication.Flexural pivots can therefore be a substitute for bearings inapplications where friction and/or the need for lubrication areconcerns.

BRIEF DESCRIPTION OF THE DRAWINGS

Features and advantages of the invention will be apparent from thedetailed description which follows, taken in conjunction with theaccompanying drawings, which together illustrate, by way of example,features of the invention; and, wherein:

FIG. 1A is an illustration of a flexural pivot in accordance with anexample of the present disclosure.

FIG. 1B is an exploded view of the flexural pivot of FIG. 1A.

FIG. 2 illustrates a flexible blade unit of the flexural pivot of FIGS.1A and 1B.

FIG. 3 illustrates a first flexure support member of the flexural pivotof FIGS. 1A and 1B.

FIG. 4 illustrates a second flexure support member of the flexural pivotof FIGS. 1A and 1B.

FIG. 5 illustrates a third flexure support member of the flexural pivotof FIGS. 1A and 1B.

FIG. 6A is an illustration of a flexural pivot manufacturing system inaccordance with an example of the present disclosure.

FIG. 6B is an exploded view of the flexural pivot manufacturing systemof FIG. 6A.

Reference will now be made to the exemplary embodiments illustrated, andspecific language will be used herein to describe the same. It willnevertheless be understood that no limitation of the scope of theinvention is thereby intended.

DETAILED DESCRIPTION

As used herein, the term “substantially” refers to the complete ornearly complete extent or degree of an action, characteristic, property,state, structure, item, or result. For example, an object that is“substantially” enclosed would mean that the object is either completelyenclosed or nearly completely enclosed. The exact allowable degree ofdeviation from absolute completeness may in some cases depend on thespecific context. However, generally speaking the nearness of completionwill be so as to have the same overall result as if absolute and totalcompletion were obtained. The use of “substantially” is equallyapplicable when used in a negative connotation to refer to the completeor near complete lack of an action, characteristic, property, state,structure, item, or result.

As used herein, “adjacent” refers to the proximity of two structures orelements. Particularly, elements that are identified as being “adjacent”may be either abutting or connected. Such elements may also be near orclose to each other without necessarily contacting each other. The exactdegree of proximity may in some cases depend on the specific context.

An initial overview of the inventive concepts is provided below and thenspecific examples are described in further detail later. This initialsummary is intended to aid readers in understanding the examples morequickly, but is not intended to identify key features or essentialfeatures of the examples, nor is it intended to limit the scope of theclaimed subject matter.

A variety of flexural pivots are commercially available for variety ofapplications. Common problems with typical commercial off-the-shelf(COTS) flexural pivots that have brazed joints are repeatableperformance and reliability, particularly where high performance anddurability are required for the application. This may be due to thedifficulty in manufacturing flexural pivots in a commercially viablemanner. Additionally, applications that require relatively large angularranges of motion may cause stresses that exceed the strength of COTSflexural pivots, often resulting in brazed joint failures. Thus, it isdesirable to develop a flexural pivot design that provides highperformance, large angular travel, and reliability while beingrelatively simple and cost-effective to produce.

Accordingly, a flexural pivot is disclosed with brazed joints that canprovide high performance, large range of motion, and reliability andthat is readily able to be manufactured. The flexural pivot can includea plurality of flexure support members, each flexure support memberhaving a plurality of flexure openings and a plurality of wells each influid communication with a respective flexure opening. The flexuralpivot can also include at least one flexure to rotatably couple theplurality of flexure support members to one another. The at least oneflexure can have first and second flexible blades arranged in a crossconfiguration. The first and second flexible blades can be disposed inthe flexure openings of the flexure support members, and braze materialor other coupling material (e.g. an epoxy or other adhesive) depositedin the flexure openings can couple the first and second flexible bladesto the flexure support members.

In one aspect, a flexural pivot precursor is disclosed. The flexuralpivot precursor can comprise a plurality of flexure support members,each flexure support member having a plurality of flexure openings and aplurality of wells each in fluid communication with a respective flexureopening. The flexural pivot precursor can also include at least oneflexure to rotatably couple the plurality of flexure support members toone another. The at least one flexure can have first and second flexibleblades arranged in a cross configuration. The first and second flexibleblades can be disposed in the flexure openings of the flexure supportmembers.

A flexural pivot manufacturing system is also disclosed. The system cancomprise a fixture having a bottom support and a top support coupled tothe bottom support. The system can also comprise a plurality of flexuralpivot support member workpieces coupled to the fixture. The plurality offlexural pivot support member workpieces can include a first flexuralpivot support member workpiece supported by and coupled to the bottomsupport, and a second flexural pivot support member workpiece supportedby and coupled to the top support. The top and bottom supports canfacilitate formation of flexure openings and wells in fluidcommunication with the flexure openings extending into ends of theflexural pivot support member workpieces to form flexural pivot flexuresupport members. The top and bottom supports can also facilitatedisposing at least one flexure in the flexure openings. The at least oneflexure can have first and second flexible blades arranged in a crossconfiguration. In addition, the top and bottom supports can facilitatedisposing braze or other coupling material in the wells to couple the atleast one flexure to the flexural pivot flexure support members toprovide for rotational movement of the flexural pivot flexure supportmembers relative to one another.

In addition, a method for making a flexural pivot is disclosed. Themethod can comprise coupling a plurality of flexural pivot supportmember workpieces to a fixture, wherein a first flexural pivot supportmember workpiece is coupled to a bottom support of the fixture, and asecond flexural pivot support member workpiece is coupled to a topsupport of the fixture. The method can also comprise coupling the topand bottom support to one another. The method can further compriseforming flexure openings and wells in fluid communication with theflexure openings extending into ends of the flexural pivot supportmember workpieces to form a plurality of flexural pivot flexure supportmembers. The method can even further comprise disposing at least oneflexure in the flexure openings of the plurality of flexural pivotflexure support members, wherein the at least one flexure has first andsecond flexible blades arranged in a cross configuration. The method canstill further comprise disposing coupling material in the wells.Additionally, the method can comprise heating the coupling materialsufficient to cause the coupling material to flow into the flexureopenings to couple the at least one flexure to the flexural pivotflexure support members and thereby rotatably couple the plurality offlexural pivot flexure support members to one another. With respect tothe coupling of the at least one flexure to the flexural pivot flexuresupport members, the method can alternatively comprise disposing anepoxy or other adhesive in the wells, wherein the epoxy or otheradhesive comprises a viscosity sufficient to facilitate wicking of theepoxy or other adhesive into the flexure openings via capillary action.

One example of a flexural pivot 100 is illustrated in FIGS. 1A and 1B.The flexural pivot 100 can comprise flexure support members rotatablycoupled to one another. For example, the flexural pivot 100 can includea first flexure support member 110, a second flexure support member 120rotatably coupled to the first flexure support member 110 for relativerotation about a first axis 101, and a third flexure support member 130rotatably coupled to the second flexure support member 120 for relativerotation about a second axis 102. The axes 101, 102 can be orthogonal.Although three flexure support members 110, 120, 130 are illustrated, itshould be recognized that a flexural pivot 100 can include only twoflexure support members coupled to one another for relative rotationabout only a single axis.

The flexural pivot 100 can be coupled to external structures tofacilitate relative rotation of the structures about the first andsecond axes 101, 102. For example, the flexural pivot 100 can be coupledto and utilized with fast steering mirrors, which are commonly used inelectro-optical sensors, directed energy systems, long range lasercommunications systems, telescopes, or other precision opticsapplications, and therefore may be included in laboratory-based systems,airborne line of sight stabilization systems, satellites, cameras, etc.Thus, one structure can be an optical bench of an electro-opticalsensor, and the other structure can be a mirror. The external structurescan be coupled to the first and third flexure support members 110, 130utilizing coupling interfaces such as openings or holes 103 (which canbe threaded), slots, pins, studs, and other coupling interfaces.

The flexural pivot 100 can include flexures 140 a-d (i.e., cross bladeflexures) rotatably coupling the first, second and third flexure supportmembers 110, 120, 130 to one another. For example, the flexures 140 a-bcan rotatably couple the first and second flexure support members 110,120 to one another, and the flexures 140 c-d can rotatably couple thesecond and third flexure support members 120, 130 to one another. Thus,the first and second flexure support members 110, 120 can move relativeto one another about the first axis 101, and the second and thirdflexure support members 120, 130 can move relative to one another aboutthe second axis 102, which can provide relative rotation of the firstand third flexure support members 110, 130 about two axes or in twodegrees of freedom. Two or more flexures can be utilized for a givenaxis to provide stability for the flexure support members. The secondflexure support member 120 moves in only a single degree of freedom withrespect to each of the first and third flexure support members 110, 130.The second flexure support member 120 may be referred to as a couplerdue to its intermediate relationship with respect to the first and thirdflexure support members 110, 130 and function coupling the two-axisrotational movement of the flexural pivot 100. In one aspect, theflexural pivot 100 can provide a frictionless pivot coupling between twobodies (i.e., external structures) that can support significant loadsduring high accelerations and allow large angular travel. In addition,the flexural pivot 100 can be designed such that the masses of all themoving parts are balanced at the same center of gravity. For example,the second flexure support member 120 or coupler can be configured soits center of gravity is at the intersection of both the first andsecond pivot axes 101, 102, which allows its weight to not affect thebalancing of the supported or moving mass in both axes.

Each flexure 140 a-d can have two or more flexible blades 141 arrangedin a cross configuration. For example, the flexible blades 141 can havea C-shape or configuration. The flexible blades 141 can be oriented withthe open sides of the C-shapes facing and oriented about 90 degreesrelative to one another to achieve the cross blade configuration. Aflexible blade 141 is shown isolated in FIG. 2. The flexible blades 141can have any suitable dimension, as the principles disclosed hereinprovide flexural pivot components that are scalable to accommodate awide range of sizes and applications. In one example, a flexural pivot100 can have an overall size dimension (e.g., length and/or width) of1.86 inches, and the flexible blades 141 can have a thickness of 0.012inches. The flexible blades 141 can be made of any suitable material. Insome examples, the flexible blade 141 can be made of materials havingrelatively high yield and fatigue strength, such as steel (e.g.,high-carbon spring stainless steel), or titanium (e.g., 6Al-4V).

Each of the first, second and third flexure support members 110, 120,130 can have flexure openings 150, 151, which can be configured as slotsto receive the flexible blades 141. The flexure openings 150, 151 canextend into ends of the first, second and third flexure support members110, 120, 130. In addition, each of the first, second and third flexuresupport members 110, 120, 130 can have wells 152, 153 (e.g., braze oradhesive wells) in fluid communication with the flexure openings 150,151 to facilitate coupling the flexible members 141 to the flexuresupport members 110, 120, 130. Braze material or another type ofcoupling material (e.g., epoxy or other adhesive) (not shown) can bedisposed in the wells 152, 153. A braze material can be heated andcaused to flow from the wells 152, 153 into the flexure openings 150,151 about the flexible members 141 to couple the flexible members 141 tothe first, second and third flexure support members 110, 120, 130. Forclarity, flexure openings 150, 151 and wells 152, 153 of the first,second and third flexure support members 110, 120, 130 are onlyidentified on portions of the second and third flexure support members120, 130 in FIGS. 1A and/or 1B. These features are shown in FIGS. 3-5and identified with the same reference numbers associated with eachindividually illustrated flexure support member. Using an epoxy or otheradhesive to couple the flexible members 141 to the first, second andthird flexure support members 110, 120, 130, the adhesive can beselected as having a sufficient viscosity to facilitate wicking of theadhesive into the flexure openings 150, 151 via capillary action.Although it is contemplated that various coupling materials can be used,the following detailed description and the examples presented will beillustrated using a braze material as the example coupling material.However, this is not intended to be limiting in any way.

The wells 152, 153 can be located at ends of the flexure openings 150,151 (e.g., radially outward relative to the flexure openings 150, 151).This can locate the wells 152, 153 proximate to or disposed aboutportions of the flexible blades 141 that are disposed in the flexureopenings 150, 151 to facilitate coupling the flexible blades 141 to thefirst, second and third flexure support members 110, 120, 130. Theflexible blades 141 can be disposed in the flexure openings 150, 151,which can be configured as slots, such that side walls of the flexureopenings 150, 151 are disposed on opposite sides of coupling portions142 a, 142 b of the flexible blades 141. For example, as shown in FIG.1B, a flexible blade 141 can be disposed in the flexure opening 150 ofthe third flexure support member 130, such that side walls of theflexure opening 150 are disposed on opposite sides of a coupling portion142 a of the blade. In addition, the same flexible blade 141 can bedisposed in the flexure opening 150 of the second flexure support member120, such that side walls of the flexure opening 150 are disposed onopposite sides of a coupling portion 142 b of the blade 141. Each of theflexible blades 141 can be similarly disposed in the other flexureopenings 150, 151 of the flexure support members 110, 120, 130. In someembodiments, the flexible blades 141 can extend at least partially intothe wells 152, 153.

The wells 152, 153 can have any suitable shape or configuration. Forexample, the wells 152, 153 can comprise cylindrical openings orientedto extend along the radially outward ends of the flexure openings 150,151 or along ends 143 a, 143 b of the flexible blades 141. In addition,the flexure openings 150, 151 can be configured to facilitate a brazedcoupling with the flexible blades 141 while maintaining braze materialwithin the flexure openings 150, 151 away from the free length orbending portion 144 between the coupling portions 142 a, 142 b of theflexible blades 141. For example, the flexure openings 150, 151 can“neck down” or narrow away from the wells 152, 153. This geometry of theflexure openings 150, 151 combined with the presence of the flexibleblade 141 can capture or limit the flow or capillary action of brazematerial away from the wells 152, 153. The side walls of the flexureopenings 150, 151 can therefore be configured to maintain or confine thebraze material in the flexure openings 150, 151 and prevent or limitbraze material from contacting the bending portions 144 of the flexibleblades 141. The side walls defining the flexure openings 150, 151 can beprecisely formed to engage with the blades 141 and accommodate brazematerial and/or block braze material flow.

By brazing or capturing the coupling portions 142 a, 142 b of theflexible blade 141 within the flexure openings 150, 151 with brazematerial originating proximate the outside ends 143 a, 143 b or edges ofthe flexible blades 141, the bending portion 144 between the couplingportions 142 a, 142 b of the flexible blades 141 can be preciselycontrolled, which can provide repeatable and predictable performance ofthe flexural pivot 100. In addition, with the braze material beingremotely located from the bending portions 144 (i.e., not located atjunctions of the bending portions and the flexure support members),braze material is kept away from the bending portions 144 (which aresubject to fatigue), and stress concentrations in the bending portions144 can be reduced or minimized. Thus, angular travel can be increasedfor the same bending portion length without failure of the blades. Inaddition, because the bending portion 144 of the blade 141 does notterminate at the braze material, the braze material does not experiencebending stress. The flexural performance of the blades 141 are thereforenot limited by the braze couplings with the flexure support members 110,120, 130. Although braze material is not illustrated in FIG. 1A forclarity in showing certain aspects of the present disclosure, the brazematerial can be located in the flexure openings 150, 151 between theflexible blades 141 and the side walls of the flexure openings 150, 151in the flexure support members 110, 120, 130. As illustrated (i.e.,without braze material), FIG. 1A shows a flexural pivot precursor inaccordance with one example of the present disclosure.

In one aspect, the bending portions 144 of the flexible blades 141 canbe prevented from contacting adjacent components (e.g., another flexibleblade 141 and/or a flexure support member 110, 120, 130 to which theflexible blade 141 is coupled) to facilitate smooth, unrestrictedmovement of the flexible blades 141 during operation. For example, thebending portions 144 of the flexible blades 141 can be recessed 145, 146on outer sides of the flexible blades 141 to prevent the bendingportions 144 from contacting adjacent components. In other words, anouter edge or surface of the bending portion 141 may not be coplanar orflush with the outer edge or surfaces of the coupling portions 142 a,142 b. In addition, the flexible blades 141 can have a C-shape orconfiguration to facilitate arranging two flexible blades 141 in a crossconfiguration while providing bending portions 144 that are offset fromone another. For example, the recess 146 can be much larger than therecess 145, thus effectively positioning the bending portion 144laterally offset with respect to the coupling portions 142 a, 142 b.This configuration can maximize the lateral size of the couplingportions 142 a, 142 b to improve coupling integrity with the flexuresupport members 110, 120, 130. As shown in FIGS. 1A and 1B, the flexibleblades 141 can be substantially identical.

In one aspect, the first, second and third flexure support members 110,120, 130 can include travel stops 159 a, 159 b to mechanically limit arotational range of motion of the flexible blades 141. The opposingtravel stops 159 a, 159 b of the flexure support members can beconfigured to contact one another at the rotational travel limits. Thetravel stops 159 a, 159 b can limit the range of motion to any suitabledegree. Typically, the travel stops 159 a, 159 b will be configured toprevent excessive bending of the flexible blades 141 that may result infailure (e.g., yielding) of the blades. The travel stops 159 a, 159 bcan have any suitable configuration or interface surface to contactopposing travel stops. The travel stops 159 a, 159 b can be defined atleast partially by the outer side surfaces 155, 156 of the flexuresupport members 110, 120, 130.

FIGS. 6A and 6B illustrate a flexural pivot manufacturing system 160 inaccordance with an example of the present disclosure. The manufacturingsystem 160 can include a fixture 161 having a bottom support 170 and atop support 180. The top and bottom supports 180, 170 can be configuredto facilitate manufacturing and assembly of a flexural pivot, such asthe flexural pivot 100 described above. Thus, the manufacturing system160 can include flexural pivot support member workpieces 110′, 120′,130′ coupled to the fixture 161. A complete flexural pivot 100(excluding braze material) is shown in FIGS. 6A and 6B to demonstratehow the fixture 161 can be used to facilitate certain manufacturing andassembly steps in a method for making a flexural pivot 100. Thus, itshould be recognized that flexural pivot support member workpieces 110′,120′, 130′ can be at any suitable stage of manufacture when the fixture161 is utilized. The first, second and third flexure support members110, 120, 130 can be made of any suitable material, such as titanium orsteel.

The workpieces 110′, 120′, 130′ for manufacturing the three flexuresupport members 110, 120, 130 can be coupled to and supported by thefixture 161. For example, the flexural pivot support member workpiece110′ that will form the first flexure support member 110 can besupported by and coupled to the top support 180. The flexural pivotsupport member workpiece 130′ that will form the third flexure supportmember 130 can be supported by and coupled to the bottom support 170.The flexural pivot support member workpiece 120′ that will form thesecond flexural pivot flexure support member 120 can be disposed betweenthe other flexural pivot support member workpieces 110′, 130′. Theworkpiece 120′ can be supported by and coupled to the top support 180and/or the bottom support 170. In the illustrated example, the flexuralpivot support member workpiece 120′ that will form the second flexuralpivot flexure support member 120 is coupled to the bottom support 170.The flexural pivot support member workpieces 110′, 120′, 130′ can becoupled to the bottom and top supports 170, 180 by fasteners 190, 191and/or pins 193, which can utilize any suitable coupling interface, suchas the holes or openings 103 and/or slots. In addition, the bottom andtop supports 170, 180 can be coupled to one another, such as byfasteners 192 and/or pins 195. The pins 193, 195 can be used toprecisely position the top support 180, the bottom support 170, and/orthe various flexural pivot support member workpieces 110′, 120′, 130′relative to one another. Pivot flexure interface surfaces of the fixture161, such as the interface surface 171 of the bottom support 170, can beconfigured to interface with outer (e.g., top and bottom) surfaces ofthe flexural pivot 100 to mount and support the workpieces 110′, 120′,130′ during manufacture and assembly. In one aspect, the interfacesurface 171 can be recessed and sidewalls 172 of the recess can serve aslocating or positioning features for the flexure support memberworkpieces 110′, 120′, 130′.

The fixture 161 can include standoff spacers 162 located in the cornersof the flexural pivot support member workpieces 110′, 120′, 130′ (i.e.,adjacent to sides of the workpieces 110′, 120′, 130′ to position the topand bottom supports 180, 170 relative to one another and therebyposition the flexural pivot support member workpieces 110′, 120′, 130′relative to one another. In other words, the standoff spacers 162 canform four legs located in four concave corners of the flexural pivotsupport member workpieces 110′, 120′, 130′. The standoff spacers 162 canbe associated with the top support 180 and/or the bottom support 170. Inthe illustrated embodiment, the standoff spaces 162 are associated withthe bottom support 170. The top and bottom supports 180, 170 of thefixture 161 can have a plate or block configuration and the standoffspacers 162 can be disposed between the plates or blocks. This fixtureconfiguration of top and bottom supports and standoff spacers 162 canexpose the ends of the flexural pivot support member workpieces 110′,120′, 130′, which can facilitate formation of the flexure openings 150,151 and wells 152, 153, which is described below.

The top and bottom supports 180, 170 of the fixture 161 can beconfigured to facilitate formation of the flexure openings 150, 151,described above with respect to FIGS. 1A-5, to form the first, secondand third flexure support members 110, 120, 130. The flexure openings150, 151 can be formed in the workpieces 110′, 120′, 130′ in anysuitable manner utilizing any suitable process or combination ofprocesses. For example, the flexure openings 150, 151 may be formed inthe workpieces 110′, 120′, 130′ by a material removal process, such asmachining. Example machining processes include electrical dischargemachining (EDM), water jet cutting, milling, etc. A manufacturingprocess may be selected based on the design objectives, tolerancerequirements, cost, etc. A wire EDM process may provide precisemachining that can meet tight tolerances and accurately control theflexure openings 150, 151. In one aspect, utilizing a common fixture 161to support the first, second and third flexure support member workpieces110′, 120′, 130′ can establish and maintain precision mountingrelationships during machining or material removal operations that formthe flexure openings 150, 151. Thus, flexure openings 150, 151 can beformed in the same fixture setup and at the same time to ensure properalignment of the flexure openings 150, 151 for the flexible blade 141.This can minimize stresses induced in the blades 141 during assembly dueto misalignment, which can provide predictable performance of theflexural pivot 100. The cuts can be generally in radial directions or,in other words, radially inward and outward relative to the axes ofrotation 101, 102. The flexure openings 150, 151 and the wells 152, 153can be formed with the same material removal operation.

In one aspect, the flexure support members 110, 120, 130 and the fixture161 can be designed to allow the assembly-level formation of the flexureopenings 150, 151 to ensure alignment of the flexure openings 150, 151for assembly with the flexible blades 141. For example, with the first,second and third flexure support members 110, 120, 130 in the“assembled” relationship shown in FIG. 1B, projected profiles of theflexure openings 150, 151 and/or the wells 152, 153 can extenduninterrupted by adjacent flexure support members in directions parallelto an axis of rotation 101, 102 associated with a given flexure 140 a-d.In other words, the geometry of the first, second and third flexuresupport members 110, 120, 130 can be such that a line of sight along theflexure openings 150, 151 and/or the wells 152, 153 for a given flexuresupport member is not blocked by an adjacent or neighboring flexuresupport member. This attribute can facilitate manufacture of the flexuresupport members 110, 120, 130 coupled together in a common jig orfixture 161, such as by wire EDM.

As an example, the flexure openings 150 in the flexure support member120, shown in FIGS. 1B and 4, can be made simultaneously with the samemanufacturing processes, such as wire EDM. For example, holes in a topcross portion 121 of the flexure support member 120 can be formed (e.g.,by drilling) as a starting location for a wire EDM process. The holescan be located across a gap or recess 122 from one another. The samedrilling operation can form both holes. The holes can form the wells 152or the wells can be finish machined by a wire EDM process. The wire forthe EDM process can extend through both holes to machine both flexureopenings 150 in the top cross portion 121 with the same wire EDM processat the same time. Because the flexure support member 130 is disposed inthe assembled position during the machining processes, the flexuresupport member 130 can include a gap or recess 132 (FIG. 5) that isconfigured to provide clearance for the drill, wire, etc. used to formthe wells 152 and the flexure openings 150 in the top cross portion 121of the second flexure support member 120. This sort of clearancerelationship between adjacent flexure support members and part featuresto be machined (e.g., flexure openings and wells) can be replicatedthroughout the pivot flexure to facilitate simultaneous fixturing andmachining of such features in all three of the first, second and thirdflexure support members 110, 120, 130.

Cutting or forming the flexure openings 150, 151 in the same fixturesetup can provide good alignment of the flexure openings. This canreduce or minimize displacement driven stresses in the blades due tomisalignment of the flexure openings 150, 151. Once the flexure openings150, 151 have been formed, the flexure support members 110, 120, 130 canbe removed from the fixture 161 and cleaned prior to final assemblywhere the flexure support members are again secured in the fixture 161and receive the flexible blades 141 in the flexure openings 150, 151, asdescribed above with respect to FIGS. 1A-5.

The flexible blades can be manufactured utilizing any suitable processor technique, such as milling, EDM, water jet machining, casting,forging, stamping, photochemical machining (PCM), laser cutting, etc. Awire EDM, PCM, and/or laser cutting process may be utilized to provideaccurate control of the part geometry. Final surfaces may be achieved bygrinding, honing, polishing, etc. to a desired geometric and/ordimensional tolerance, and/or surface finish.

The top and bottom supports 180, 170 can be configured to facilitatedisposing the flexible blades 141 in the flexure openings 150, 151 torotatably couple the first, second and third flexure support members110, 120, 130 to one another. For example, the top and bottom supports(including standoff spacers 162) can provide access to ends of thefirst, second and third flexure support members 110, 120, 130 tofacilitate disposing the flexible blades 141 in the flexure openings150, 151 of the first, second and third flexure support members 110,120, 130. By providing sufficient space about the ends of the flexuresupport members 110, 120, 130, the flexible blades 141 can be insertedinto the flexure openings 150, 151. In addition, supporting the first,second and third flexure support members 110, 120, 130 in the fixture161 can align the flexure openings 150, 151 to facilitate stress-freeassembly of the blades 141 prior to brazing.

With the flexure support members 110, 120, 130 fixtured or fixed and theflexible blades 141 disposed in the flexure openings 150, 151 asillustrated in FIGS. 1A and 1B, braze material can be disposed in thewells 152, 153 to couple the flexible blades 141 to the flexure supportmembers. This configuration can represent a flexural pivot precursor inaccordance with one example of the present disclosure. As describedherein, the top and bottom supports 180, 170 can be configured tofacilitate coupling the flexible blades 141 to the flexure supportmembers 110, 120, 130, such as by providing access to the ends of theflexure support members for putting braze material in the wells 152,153. Any suitable type of braze material in any suitable configurationmay be utilized. For example, braze material in wire form can bedisposed in the wells 152, 153. Alternatively, braze material in foilform can be disposed about the ends of the flexible blades 141. In thiscase, the braze material can be initially located in the wells 152, 153and/or in the flexure openings 150, 151.

With braze material disposed in the wells 152, 153, the braze materialcan be heated sufficiently to cause the braze material to flow (e.g.,via capillary action) into the flexure openings 150, 151 about theflexible blades 141 to couple the flexible blades to the flexure supportmembers 110, 120, 130. The braze material can be heated in any suitablemanner, such as by disposing the manufacturing system 160 in a furnace.Thus, the same fixture 161 can be used to support the parts through abrazing operation. Brazing the flexible blades 141 to the flexuresupport members 110, 120, 130 in the same fixture 161 can ensure properalignment of the blades 141 as they are brazed. The flexible blades 141can therefore be brazed in a single brazing operation with nopost-machining necessary. The principles disclosed herein can providesuperior brazed connections than that available in COTS flexural pivots.

As indicated above, although brazing has been discussed herein as theexemplary way to couple the flexible blades to the flexure supportmembers, such is not intended to be limiting in any way. For example, itis contemplated that the flexible blades can be coupled to the flexuresupport members using an epoxy or other adhesive, which can be injectedinto the wells. The epoxy or other adhesive can comprise a viscositysufficient to cause the epoxy or other adhesive to wick into the flexureopenings via capillary action. Those skilled in the art will recognizestill other ways that the flexible blades can be coupled to the flexuresupport members.

It is noted that no specific order is required in the methods disclosedherein, though generally in some embodiments, method steps can becarried out sequentially.

It is to be understood that the examples set forth herein are notlimited to the particular structures, process steps, or materialsdisclosed, but are extended to equivalents thereof as would berecognized by those ordinarily skilled in the relevant arts. It shouldalso be understood that terminology employed herein is used for thepurpose of describing particular examples only and is not intended to belimiting.

Furthermore, the described features, structures, or characteristics maybe combined in any suitable manner in one or more examples. In thedescription, numerous specific details are provided, such as examples oflengths, widths, shapes, etc., to provide a thorough understanding ofthe technology being described. One skilled in the relevant art willrecognize, however, that the invention can be practiced without one ormore of the specific details, or with other methods, components,materials, etc. In other instances, well-known structures, materials, oroperations are not shown or described in detail to avoid obscuringaspects of the invention.

While the foregoing examples are illustrative of the principles of theinvention in one or more particular applications, it will be apparent tothose of ordinary skill in the art that numerous modifications in form,usage and details of implementation can be made without the exercise ofinventive faculty, and without departing from the principles andconcepts described herein. Accordingly, it is not intended that theinvention be limited, except as by the claims set forth below.

What is claimed is:
 1. A flexural pivot manufacturing system,comprising: a fixture having a bottom support and a top support coupledto the bottom support; and a plurality of flexural pivot support memberworkpieces coupled to the fixture, the plurality of flexural pivotsupport member workpieces including a first flexural pivot supportmember workpiece supported by and coupled to the bottom support, and asecond flexural pivot support member workpiece supported by and coupledto the top support, wherein the top and bottom supports facilitateformation of flexure openings and wells in fluid communication with theflexure openings extending into ends of the flexural pivot supportmember workpieces to form flexure support members, disposing at leastone flexure in the flexure openings, wherein the at least one flexurehas first and second flexible blades arranged in a cross configuration,and disposing coupling material in the wells to couple the at least oneflexure to the flexure support members to provide for rotationalmovement of the flexure support members relative to one another.
 2. Thesystem of claim 1, wherein the flexure openings are configured as slots.3. The system of claim 1, wherein the first and second flexural pivotsupport member workpieces are coupled to the bottom and top supports,respectively, by fasteners.
 4. The system of claim 1, wherein theplurality of flexure support members comprises a third flexure supportmember disposed between the first and second flexure support members andsupported by and coupled to at least one of the top support and thebottom support.
 5. A method of making a flexural pivot, comprising:coupling a plurality of flexural pivot support member workpieces to afixture, wherein a first flexural pivot support member workpiece iscoupled to a bottom support of the fixture, and a second flexural pivotsupport member workpiece is coupled to a top support of the fixture;coupling the top and bottom support to one another; forming flexureopenings and wells in fluid communication with the flexure openingsextending into ends of the flexural pivot support member workpieces toform a plurality of flexure support members; disposing at least oneflexure in the flexure openings of the plurality of flexure supportmembers, wherein the at least one flexure has first and second flexibleblades arranged in a cross configuration; disposing a coupling materialin the wells; and heating the coupling material sufficiently to causethe coupling material to flow into the flexure openings to couple the atleast one flexure to the flexure support members and thereby rotatablycouple the plurality of flexure support members to one another.
 6. Themethod of claim 5, wherein the flexure openings are configured as slots.7. The method of claim 5, wherein forming the flexure openings and wellscomprises removing material from the flexure support members.
 8. Themethod of claim 7, wherein removing material from the flexure supportmembers comprises performing an electrical discharge machining (EDM)operation.
 9. The method of claim 7, wherein at least some of theflexure openings of the flexure support members are formed in the samematerial removal operation.
 10. The method of claim 7, wherein at leastsome of the wells of the flexure support members are formed in the samematerial removal operation.
 11. The method of claim 5, wherein the firstand second flexural pivot support member workpieces are coupled to thebottom and top supports, respectively, by fasteners.
 12. The method ofclaim 5, wherein the plurality of flexural pivot support memberworkpieces comprises a third flexural pivot support member workpiecedisposed between the first and second flexural pivot support memberworkpieces, the third flexural pivot support member workpiece beingsupported by and coupled to at least one of the top support and thebottom support.
 13. The method of claim 5, wherein the fixture comprisesstandoff spacers located at sides of the flexural pivot support memberworkpieces to position the top and bottom supports relative to oneanother and thereby position the flexural pivot support memberworkpieces relative to one another.
 14. The method of claim 13, whereinthe top and bottom supports and the standoff spacers of the fixtureexpose the ends of the flexural pivot support member workpieces tofacilitate formation of the flexure openings and wells.
 15. The methodof claim 13, wherein the standoff spacers are associated with at leastone of the top support and the bottom support.